2. Wood’s Lamp Examination
Mercury vapour UV lamp with an incoorporated Wood’s filter (barium silicate glass with 9% metal oxide.
Emits UV rays in the wavelength of 360 nm

3. Wood’s Lamp Examination
Uses
Diagnosis of taenia capitis
Gives rise to greenish fluorescence
Microsporum species and trychophyton schoenleonii are the main fluorescing species
Diagnosis of bacterial infections
Erythrasema gives a coral pink colouration

4. Examination of extent of pigmentary disorders
Easily accentuates the distinction between slightly hypopigmented and normal skin areas
Enhances the hypopigmented lesions e.g. ash leaf macules in light skin patients
Diagnosis of porphyria
Pinkish red or orangish red fluoresence in urine which is intensified on addition of dilute HCl
Similar fluoresence in faeces

5. Detection of drug deposits
Demonstrates yellow fluoroscence deposits in teeth and mepacrine in nails

6. Mycologic Examination
KOH Mount
Sample is put on a glass slide and an aquous solution of 20% KOH is addedbefore applying the cover slip
Examine the slide under microscope after min
Fungal hyphae are easily visible

8. KOH Mount Specimens to be taken Disease suspected Specimen
Tinea corporis
Tinea cruris
Tinea unguium
Tinea capitis
Ptyriasis versicolor
Candidiasis
Scales/roof of vesicles
Nail clippings, Subungual debris
Plucked hair, Scales
Scales
Contents of pustule, Vaginal discharge

9. Diagnosis of Scabies
Presence of mite,ova or faeces in scrapings of paules,vesiculesor burrows confirms the diagnosis
METHOD
Drop of mineral oil placed on a sterile scalpel blade is applied onto a lesion which is then scrapped vigrously till tiny flecks of blood are visible in the oil.The material is transferred onto a glass slide and examined for mites,ova or faeces

10. Tzanck Test Cytological examination of skin blisters
Test is done in vescicular and bullous lesions
METHOD
Early lesion is choosen,deroofed and the excess fluid is gently blotted with gauze.The floor of the blister is then scrapped gently with a scalpel blade and the material so obtained is spread on a glass slide and stained with Giemsa stain

11. Role of Tzack smear in diagnosis of skin conditions
Tzanck Test
Role of Tzack smear in diagnosis of skin conditions
Microscopic findings
Diagnosis
Acantholytic cells
Multinucleated giant cells
Pemphigus
Herpes simplex & Herpes zoster

12. PATCH TESTS
Detects antigens responsible for type IV allergy (allergic contact dermatitis)
Antigens Used
Test the suspected antigen as well as antigens which are present in the material which is likely to be used as a substitute
If theseare not known a standard battery of antigens can be used

14. Interpretations of patch tests
Clinical findings
Grading
No reaction
Doubtful reaction
Weak reaction
Strong reaction
Extreme reaction
Irritant reaction
Normal skin
Minimal erythrema
Erythrema
Erythrema and oedema
Erythrema and vescicular/bullous findings
Cautrisation 1+ 2+ 3+ 4+ IR

15. PHOTOPATCH TESTING
Done to establish cause in photoallergic contact dermatitis
METHOD
Antigens are applied,as in routine pach testing but in duplicate.
At 24 hrs , one set of patches are irradiated with UVA

16. Interpretation of photopatch test
Reading at site exposed to UVA
Reading at unexposed site
Interpretation - ++ +
No allergy
Photoallergy
Contact allergy
Contact allergy with photoaggravation

17. SKIN BIOPSY Techniques of Taking Biopsy Two common techniques
Punch biopsy
Scalpel biopsy

18. Punch Biopsy
Punch biopsies can be done rapidly, with or without suturing of the wound
A punch-biopsy instrument of appropriate size is needed
METHOD
A local anesthetic is usually injected at the site. The operator rotates the instrument until it penetrates to the subcutaneous level. The circle of tissue is then removed. Bleeding can be stopped with pressure or by the use of one or two sutures. An elliptical wound instead of a circular wound can be produced by stretching the skin perpendicular to the desired suture line before the punch is rotated. The resultant scar, after suturing, is neater
Punch biopsies are inadequate for evaluation of vesiculobullous diseases

19. Scalpel Biopsy A scalpel is used to slice off a lesion
Performed superficially or deeply
Hemostasis can be accomplished by pressure, light electrosurgery, Monsel solution, or aluminum chloride solution
Not recommended for excision of melanocytic lesions

20. Processing of Skin Biopsy
Apart from routine H&E staining special stains can be used for various tissues and to identify different organisims
Stain
Colour
Organisms
Mycobacteria
Fungi
Fite stain
PAS
Pink
Red
Deposits
Glycogen
Acid mucopolysaccharides
Amyloid
Toluidine blue
Alcian blue
Congo red
Blue
Orange pink with apple green birefringence
Skin components
Collagen
Elastic fibres
Mast cell granules
Masson’s trichome
Verhoef-van gieson
Green
Black
Purple

21. Precautions While Taking a Skin Biopsy
Biopsy a new lesion or active edge of a proressing lesion
Avoid legs (slow healing), upper trunk(because of tendency of keloid formation),exposed parts(cosmetic objections) & bony prominces
Do not crush the tissue
Place the proper fixative
Label samples correctly

22. THANK YOU